The present intention relates to articles of aluminum containing at least one surface or parts of at least one surface which are suitable for the deposition of layers or layer systems from the gas phase on said surfaces, and their use.
It is known to manufacture strips in bright materials, for example refined aluminum or AlMg alloys based on aluminum having a degree of purity of 99.8 and higher, such as, for example, 99.9%, and rolled surfaces which produce diffuse or directed light reflection depending on application. It is also known to polish the surfaces of such strips chemically or electrolytically to increase the total reflection or directed reflection and then to produce a protective layer of, for example, 1-5 .mu.m layer thickness by anodic oxidation.
These known processes have the disadvantage that expensive bright alloys based on refined aluminum have to be used. As a result of the anodic oxide layer, the reflectivity of the surface, and in that connection both the total reflection and also the directed reflection, decreases due to absorption and light scattering, in particular in the oxide layer. This signifies an energy loss.
Chemical treatment, and in that connection the production of the degree of brightness in particular, is not without problems from the point of view of environmental pollution by effluent waters and wastes.
Finally, in the normal thickness range of 1 to 3 .mu.m, the anodic oxide layer often has troublesome interference effects, the so-called iridescence.
The object of the present invention is to avoid said disadvantages and to propose articles of aluminum which contain at least one surface or parts of at least one surface which are suitable for the deposition of layers or layer systems from the gas phase on said surfaces, and said layers or layer systems facilitate as loss-free a reflection of energy as possible.